Young honey bees Apis mellifera learn to avoid pollen contaminated with glyphosate or imidacloprid

Honey bees (Apis mellifera) play a crucial role in ecosystems by providing essential pollination services, but their performance is increasingly affected by various stressors, with agrochemicals posing a growing threat. Glyphosate (GLY), a widely used herbicide, and Imidacloprid (IMI), a common insecticide, have been shown to exert sub-lethal effects on honey bees when exposed to field-realistic concentrations. Despite this, little is known about bees' sensitivity to agrochemicals and their ability to avoid contaminated resources. In this study, we investigated whether young worker bees are capable of assessing agrochemical contamination by testing whether they learn to avoid contaminated pollen. To assess this, we quantified consumption preferences for two pure monofloral pollens before, during and after exposure to one of these pollen types contaminated with GLY or IMI at varying concentrations. Our results showed significant reductions in consumption preferences, with decreases ranging from 10.7% to 23.2% for pollen contaminated with different doses of GLY, and from 12.7% to 20.0% for pollen contaminated with different doses of IMI, suggesting that honey bees can respond to the presence of these agrochemicals and learn to avoid contaminated food. We propose that avoidance behaviour may arise when bees associate specific pollen cues with malaise experiences. Avoidance would allow bees to minimize exposure to environmental pollutants, which could enhance their ability to adapt to and survive in anthropogenic environments.